Various hydraulic powders are produced from hydraulic compounds such as Portland cement clinker and blast furnace slag by grinding these compounds. For example, a Portland cement is produced by firing raw materials containing limestone, clay, and iron slag to obtain a clinker, mixing the clinker with an appropriate amount of gypsum, and grinding the mixture. In the production, to increase a grinding efficiency, grinding aids such as diethylene glycol and triethanolamine are used. In the step of grinding, a hydraulic compound is desirably ground to an intended size as efficiently as possible. For this purpose, a grinding aid has conventionally been used in the step of grinding.
JP-A 05-147984 discloses a method for producing a high strength cement, in which a granulated material of superfine particles that is easy to handle is used in order to achieve sufficient effects of superfine particles to improve physical properties of the cement. This method contains adding not more than 50 parts by weight of granulated material having a diameter of less than 2 mm composed of superfine particles having a diameter of not more than 1 μm and a grinding aid to 100 parts by weight of a clinker, and grinding the clinker. In this patent, examples of the grinding aid include amines such as triethanolamine and diethanolamine and glycols such as diethylene glycol.
JP-A 03-183647 describes a blended cement composition to which a higher trialkanolamine having at least one hydroxyalkyl group having 3 to 5 carbon atoms such as triisopropanolamine is added in order to increase a 7-day and a 28-day compressive strength curves to clear the minimum requirements for Portland cement.
JP-A 03-183647 further describes about the higher trialkanolamine that, an iron (III) ion, generating as a by-product in a solution during hydration of C4AF, is highly insoluble at such high pH as a hydrated cement having and immediately forms an amorphous gel of iron (III) hydroxide to precipitate. The gel tends to coat cement particles to cause an overall delaying of hydration of the cement. The higher trialkanolamine used in the patent has some effects on iron complex formation at high pH to aid in removal of the iron-rich coating, thereby improving strength development of the cement (p. 7, right upper column, lines 9 to 19).
JP-A 2002-145651 describes a hydraulic composition produced from waste-derived materials such as incinerated ash of municipal solid waste or sewage sludge, in which a strength enhancer such as an alkanolamine is blended in order to increase a mechanical strength of the hydraulic composition.
WO-A 2009/022716 (corresponding to US-A 2011/0005432) describes a process of grinding a hydraulic compound in the presence of an alkylene oxide-adduct compound.
WO-A 2009/022717 (corresponding to US-A 2010/0319587) describes a process of grinding a hydraulic compound in the presence of glycerol and polyethylene glycol.
JP-B 2865149 (JP-A 03-183647) discloses an enhanced blended cement containing C4AF, gypsum, a filler, and a higher trialkanolamine.
JP-A 2000-313648 discloses a mechanical strength enhancer for cement, containing an alkanolamine and a polyoxyalkylene block copolymer.
JP-A 2006-515826 (WO-A 2004/033386) discloses an amine used as an additive for cement processing.
JP-B 48-042697 discloses an additive composition for hydraulic cement.
U.S. Pat. No. 2,203,809 discloses a manufacture of a Portland cement. US-A 2009/0050023 discloses a hardening accelerator containing an aminoalcohol.